This invention relates to a support device specifically for mounting or hanging an object on a wall or other substantially vertical surface. Present day support devices are generally of two types. The first type consists of two screw eyes, wire and a wall hook. The two screw eyes are positioned along the vertical sides of the object to be hung, such as the frame of a painting or photograph. Wire of sufficient length is threaded through the two screw eyes and attached on each end to a screw eye. The wall hook is then attached to the wall. To mount the picture on the wall the wire is placed over the wall hook. The picture is centered by moving the picture horizontally to a position where the center of gravity of the picture is vertically aligned with the wall hook. If the center of gravity is not directly below the wall hook, the force of gravity produces a moment acting about the wall hook, thereby causing the picture to rotate about that axis. The further the frame is from center, the greater the rotational force acting on the picture. The frame, for example, tilts as the center of gravity of the frame swings to a position where it is substantially below the wall hook. If the frame is positioned so that the center of gravity is close to being vertically below the wall hook, the rotational force will be small and can be counteracted by the friction between the wall and the bottom of the frame.
The second type of wall support device consists of a small sheet metal bar having a saw-toothed lower edge. The bar is attached over the center of gravity of the object with two fasteners. The wall hook, generally a nail, is placed into the wall, and the bar is hung on the nail. The object is moved horizontally from tooth to tooth until the center of gravity of the object to be hung is approximately below the nail or wall hook. Again, if the center of gravity is not vertically aligned with the wall hook, a rotational force results. This rotational force, if large enough to overcome the frictional force between the object and the wall, causes the object to tilt.
Shortcomings exist with both types of present day support devices. Both rely upon the friction force between the lower edge of the object to be hung and the wall to counteract any rotational force produced by improper alignment between the center of gravity of the object and the mounting axis of the wall support device. However, this friction force is fairly small and irregular. Both support devices can also be easily moved in a horizontal direction. These two factors result in instability in the positioning of the mounted object. Wind, vibrations in the wall, and other sources can cause the bottom of the frame to leave the wall momentarily, eliminating the friction force acting on the object. Any rotational force counteracted by the friction force will cause the object to tilt away from its horizontal or symmetrical position.
Another disadvantage in pre-existing support devices is that the vibrations in the wall can also cause the mounted objects to move horizontally. When this occurs, greater rotational forces will result. Moreover, with both types of prior art devices, the bottom edge of the hanging object contacts the wall or vertical surface. Rotational forces acting on the object will thus result in scratches and marks on the wall.
Furthermore, when both types of these devices are used, the picture or object angles out from the wall. Dust then gathers on the back of the frame resulting in additional clean-up when the picture is removed from the wall. In addition, when the object is rehung, the inconvenient and time-consuming process of leveling the picture must be repeated.
The toothed bar type of mounting device also has an additional problem when used to mount a small object. Because smaller pictures and frames weigh less, a smaller frictional force is generated. Thus, even a small rotational force cannot be counteracted and the picture will not hang level.
A further disadvantage associated with the wire, screw eye and wall hook arrangement, is that many times the wire is visible above the picture, which is, of course, quite unsightly.